COSTELLO

Explosion Investigations

& Process Safety Services

Call 310-721-0397 24 hours a day

R.C. Costello & Assoc., Inc. provides investigations of explosions in the Chemical Process Industries. We are available on an emergency basis to assist you in pin pointing the most probable cause of the explosion and can recommend and implement the required engineering and/ or procedural changes. We can also provide engineering support for the design and implementation of your emergency shutdown sequence. We have been involved with redesigns for various thermal oxidizers, electrostatic precipitators, bulk storage tanks and other process equipment. Investigations include dust, hydrocarbon vapor and hybrid systems.

There have been three major biodiesel plant incidents in 2006. R.C. Costello & Assoc., Inc. as designers of biodiesel plants, knows and understands the inherent problems with the handling and use of methanol. Our plants comply to the National Electric Code, NFPA 70, other NFPA guide lines, ASME codes, API codes, OSHA and local and state requirements. We can provide safety audits to insure your biodiesel plant is safe and in compliance. If you have had an incident (fire or explosion) we can provide the support required to get you back up and running in a safe manner. A flammability diagram for methanol is shown here. The area bound by the three lines LFL-MOC, MOC-UFL and UFL_LFL defines the flammable region for methanol vapors in air. (MOC = Minimum Oxygen of Combustion)

Services Provided

Hazardous and Operability (HAZOP) Reviews. Our background in process engineering and process safety allows us to provide comprehensive HAZOP reviews with an emphasis on practical real world recommendations in the final report.
Process safety studies for flammability and risk for chemical processes including reactors and distillation columns. This includes computer modeling.
Explosion Investigation and engineering redesign for prevention.
Preparation of flammability diagrams for your specific mixture of hydrocarbons and for all combinations of oxygen and the hydrocarbon mixture.
Equipment surveys, reviews, and process redesign. This includes flashback potential.
Diers calculations for sizing rupture disks and relief valves on new and existing reactors, columns and vessels. We also can provide laboratory assistance in determining temperature rate of rise for runaway chemical reactions.
ASTM testing for Limits of Flammability of Chemicals

Definitions

Detonation and Deflagration

Explosions are either detonations or deflagrations; the difference depends on the speed of the shock wave emanating from the explosion. In front of a flame front moving in a pipe is a pressure or shock wave. If the pressure wave moves faster than the speed of sound in the unreacted medium the explosion is a detonation; if it moves at a speed less than the speed of sound it is a deflagration.

Autoignition temperature

A fixed temperature above which a flammable mixture is capable of extracting enough energy from the environment to self-ignite.

Flammability Limits

Vapor-air mixtures will only ignite and burn over a well-specified range of compositions. The mixture will not burn when the composition is lower than the lower flammable limit (LFL); the mixture is too lean for combustion to occur. The mixture will not burn when the composition is higher than the upper flammable limit (UFL); the mixture is too rich for combustion to occur. A mixture is flammable only when the composition is between the LFL and the UFL. Typical units are volume percent fuel as a percentage of fuel and air. Lower explosive limit (LEL) and upper explosive limit (UEL) are used interchangeably with LFL and UFL.

Temperature Effects on Flammability Limits

Lower flammability limits in air are deceased approximately 8 percent by a temperature increase of 100 °C. Upper flammability limits are increased 8 percent by a temperature increase of 100 °C.

Pressure Effects of Flammability Limits

Pressure has only a slight effect on LFL. Lower limits are essentially constant down to about 5 kPa generally, below which pressure flame does not propagate. The effect of higher pressures on LFL and correspondingly on MOC is slight. On the other hand elevated pressure greatly increases the UFL.

Technical Article from September 2006 Biodiesel Magazine where Mr. Costello was Interviewed

Getting Serious about Safety (in Biodiesel Plants)

Things you should know and ask your plant designer/builder/supplier

Technical Articles from Chemical Processing Magazine by Rocky.C. Costello

Improving Performance and Safety of Thin-Film Evaporators

Flashback Prevention Helps Cure Thermal Oxidizer Explosions

Do you have a question about Process Safety?

Forums are the best source of "peer-reviewed" engineering information on the Internet! Chemical Engineers, Mechanical Engineers, Pharmaceutical Engineers, and Safety Professionals can join here:

Links to Organizations involved in the standards making process with many focusing on safety.

National:

AIChE (American Institute of Chemical Engineers)
ANSI (American National Standards Institute)
API (American Petroleum Institute)
ASME (American Society of Mechanical Engineers)
ASTM (American Society for Testing and Materials)
FM Global formerly Factory Mutual
FSSA (Fire Suppression Systems Association)
HARC (Halon Alternatives Research Corporation)
NFPA (National Fire Protection Association)
NFSA (National Fire Sprinkler Association, Inc.)
NIST (National Institute of Standards and Technology)
OSHA (Occupational Safety Health Administration)
Underwriter's Laboratories